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[Clinical significance of diffuse vasoconstriction of coronary arteries--a study using hyperventilation thallium-201
M Katamura1, A Matsumuro, S Tamagaki
1Department of Medicine, Kyoto Second Red Cross Hospital.
Insights
Thallium-201 imaging can detect myocardial ischemia in patients with diffuse vasoconstriction during ergonovine testing. This suggests medical treatment for vasospastic angina in such cases.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Coronary artery vasospasm can cause myocardial ischemia.
- Distinguishing between vasospasm and diffuse vasoconstriction is clinically important.
Purpose of the Study:
- To evaluate the utility of Hyperventilation Thallium-201 imaging in identifying myocardial ischemia.
- To assess patients with diffuse vasoconstriction during ergonovine maleate provocative testing.
Main Methods:
- Utilized Hyperventilation Thallium-201 SPECT imaging.
- Administered ergonovine maleate provocative testing.
- Analyzed myocardial perfusion defects (PD) and redistribution (RD).
- Evaluated washout rate (WOR) and lung/heart ratio changes (delta L/H%).
Main Results:
- Significant perfusion defects and redistribution were observed in patients with ergonovine-induced vasospasm (group S) and diffuse vasoconstriction (group D).
- Patients with diffuse vasoconstriction showed significantly lower mean minimum washout rate and delta L/H% compared to controls (group N).
- Findings suggest myocardial ischemia in diffuse vasoconstrictive coronary artery disease.
Conclusions:
- Hyperventilation Thallium-201 imaging is effective in detecting myocardial ischemia in diffuse vasoconstriction.
- Patients with diffuse vasoconstriction may benefit from medical management similar to vasospastic angina.
Abstract:
Hyperventilation Thallium-201 imaging was evaluated for the examination of the existence of ischemia in the cases of diffuse vasoconstriction under the ergonovine maleate provocative test for coronary artery. Transient myocardial perfusion defect (PD) was demonstrated in 14 patients with ergonovine induced vasospasm (group S), and 13 of these patients also demonstrated redistribution (RD) (92.4%). In 14 patients with diffuse vasoconstriction (group D), nine demonstrated PD, and all of them revealed RD. On the other hand, only one of ten (10%) patients demonstrated PD and RD in a group of patients without spasm or diffuse vasoconstriction (group N). In addition, the left ventricular myocardium was divided into nine segments on a SPECT image, and the mean minimum washout rate (WOR) of each segment was evaluated. These values were compared with the percent change of the lung/heart ratio between early and delayed images (delta L/H%). Both the mean minimum WOR mean and delta L/H% of group D were significantly smaller than that of group N (p < 0.001), and only approximated to group S. Thus, the possibility of myocardial ischemia of diffuse vasoconstrictive coronary artery is implicated and such patients are supposed to be treated medically as vasospastic angina.